Using heat to straighten hair has been a part of hair styling since the 1800s. The challenge was to determine the best way to accomplish this feat. Initially, irons designed to iron clothes were used by women on their hair. This approach often resulted in damaged hair from the intense heat. Heated rods were also used to straighten her hair. Eventually, these obstacles were overcome.
The application of heat is the key to effectively styling hair. Hydrogen bonds in each strand of hair cause the hair to curl. After sufficient heat is applied to the hair strand, the hydrogen bonds are broken and the hair lies straight. The more curl in the hair, the more heat is required to break up these bonds so the hair can lie flat.
One approach to applying heat to hair was the idea of hinging two flat plates together. In 1909, Isaac K. Shero received a patent for a hair-straightening device, which was comprised of two flat irons that were heated and pressed together. This product was the first known “flat iron”. But with any industry there is evolution, a desire to make a current product better. Today, many flat irons have a hinged design.
As mentioned, heat is a key element in the operation of a flat iron product. Today the most effective flat irons have ceramic heating elements. The ceramic coating on these irons is much more effective due to the ability to provide constant heat while styling. Their heat up time has been reduced to about 10 seconds.
Although there are numerous hair styling products that address various aspects of actually styling hair, little attention has been given to alternative ways of powering the hair styling devices. One explanation for the lack of attention given to powering a hair styling device is that there are few options for powering these devices. A hair styling device requires an enormous amount of heat. The primary way to supply this heat is through connecting the hair styling device to a power source. This power source is usually an outlet in a building structure. For example, batteries do not have enough power to provide the amount of heat required to adequately heat a curling iron for a sufficient amount of time.
Historically there have been three ways to power a curling iron product. One way is to directly connect the device to an AC line in a building structure. A second way incorporates a heat-storing body, which keeps heat after heating. A third way is with a rechargeable battery. The AC line type hair iron cannot be used without an AC line and lacks portability. The heat-storing device type hair iron can be used only for a short time after disconnection from the AC line, and therefore lacks portability. Similar to the heat-storing device, a battery cannot hold a sufficient amount of charge and has to be frequently recharged.
Throughout the years, there have been several modifications to hair styling devices, although few have addressed the issue of powering the hair styling device. U.S. Pat. No. 4,354,092 to Manabe et al. describes an electrically heated hair curling iron that includes a sheet-shaped heater with electrodes affixed to an electrically resistive layer, wrapped around an elongated cylindrical support, and capable of being rapidly heated and maintained hot by electric current available from a rechargeable storage battery. The resistive layer has a positive temperature coefficient of resistance so that its temperature is self-limiting. The storage battery is contained in a handle attached to the cylindrical support, and a battery charger is disclosed which comes into electrical contact with the battery when the handle is inserted in a cavity located in the battery charger. An elongated longitudinal clip is used to retain the hair in contact with the heater; a removable cap protects the heater and clip when the iron is not in use, and also engages a switch, which ensures that the iron does not remain on. The charger and the curling iron are each provided with an LED to indicate operation of the charger and state of charge of the battery, respectively. This particular approach requires removing the battery from the hair styling device and recharging the device.
The inability to supply sufficient power except through the AC source limits the portability of the device. For example, a passenger in a motor vehicle cannot use a curling iron device because the amount of power supplied through the vehicle power outlet is in sufficient to adequately heat the curling iron. In addition, an attempt to supply sufficient power and heat to the curling iron can be risky and could cause damage to the power system of the motor vehicle.
As mentioned, primary way of using a curling iron product to style hair requires the direct connection to an AC power outlet. Portable use of a curling iron would require some type of power storage system in the curling iron. The use of a battery to supply sufficient power to the curling iron product to produce enough heat to adequately style someone's hair would require a battery of an unreasonable size for this type of product. There remains a need for a device and system for supplying power to a hair styling device such as a curling iron such that such a hair styling can be used in a variety of places and not be dependent on AC outlet power source for power.